The impact of postoperative discontinuation or continuation of chronic statin therapy on cardiac outcome after major vascular surgery

Abstract

Conclusions: Discontinuation of chronic statin therapy after major vascular surgery increases the risk of myocardial infarction. Statin therapy should be reinstituted on the first postoperative day after major vascular surgery. Summary: Accumulating evidence indicates statins reduce perioperative cardiac events. It is unknown when patients who receive chronic statin therapy should resume statins after a major vascular procedure. The authors sought to compare cardiac outcomes in patients receiving chronic statin therapy who resumed statin therapy immediately postoperatively vs those where statin therapy was discontinued, at least temporarily, during the perioperative period. This was a retrospective analysis of a prospectively maintained database. Included were patients who underwent infrarenal aortic reconstruction for aneurysm or occlusive disease using endovascular or open techniques. Patients were studied from January 2001 to December 2004. Patients undergoing emergency procedures were excluded. Blood was obtained for troponin I measurements when the patient arrived to the postanesthesia care unit and on the first, second, and third postoperative days. Patients not chronically treated with statins were considered controls and did not receive perioperative statin therapy. Patients chronically treated with statins were divided into two groups. The first was the discontinuation group. These were 491 patients from January 2001 to December 2003 in which the authors’ institution did not have specific guidelines regarding postoperative statin re-administration. The continuation group consisted of 178 patients from January 2004 where guidelines were in place to continue statins up to the evening before surgery, with resumption on the first postoperative day using either nasogastric or oral administration. Intracohort (propensity score) and extracohort (Lee score) risk adjustments were performed to determine the significance of differences in elevated troponin levels in the continuation vs discontinuation groups. A troponin I level >99th percentile or >0.2 ng/mL was considered indicative of myocardial necrosis. In the discontinuation group, median delay between surgery and resumption of statin therapy was 4 days, and in the continuation group, it was 1 day (P < .001). With propensity score matching for likelihood of preoperative treatment, the odds ratio associated with chronic statin treatment to predict myonecrosis for patients with vs without early postoperative statin resumption (continuation vs discontinuation groups) was 0.38 and 2.1 (relative risk reduction, 5.4; 95% confidence interval, 1.2 to 25.3, P < .001). The odds ratio for myocardial necrosis after adjustment for the Lee score was 0.38 in the continuation group and 2.1 in the discontinuation group (P < .001). Postoperative statin withdrawal was an independent predictor of postoperative elevated troponin levels (odds ratio, 2.9; 95% confidence interval, 1.6 to 5.5). Comment: Although this was not a randomized trial and it used historic controls, the data suggest that early resumption of statin therapy in patients chronically receiving statin therapy will reduce the incidence of myocardial infarction. Although there was no difference in perioperative mortality in the continuation vs discontinuation groups, perioperative myocardial infarction in itself is an end point worth reducing. It has been associated with greater risk of long-term death and with increased duration of hospitalization. More and more evidence now suggests a deleterious cardiac effect of withdrawing statin therapy in the perioperative period.